通过T-SQL语句创建游标与实现数据库加解密功能

DECLARE @sql varchar(100);
DECLARE @TableName varchar(32);
DECLARE @FieldName varchar(32);
DECLARE @PrimaryKey varchar(32);
DECLARE @DbValue varchar(32);
DECLARE @PKey int;
 
--赋值
set @TableName='Student';
SET @FieldName='Name';
SET @PrimaryKey='Id';
--创建动态游标
set @sql = 'declare rowCursor cursor For select '+@PrimaryKey+' as PKey , '+@FieldName
+' as DbValue from '+@TableName;
EXEC(@sql);  
--打开游标
OPEN rowCursor; 
--取值
fetch next from rowCursor into @PKey,@DbValue;
--循环
while(@@FETCH_STATUS=0)
    begin
        declare @ExecSql varchar(100);
        set @ExecSql='Update '+@TableName +' set '+@FieldName+' = 234324324';
        PRINT @ExecSql
        EXEC(@ExecSql)
        fetch next from rowCursor into @PKey,@DbValue;
    end 
--关闭游标
close rowCursor;
--释放游标控件
deallocate rowCursor;

CREATE TABLE [dbo].[Users]
(
    [U_nbr] NVARCHAR(20) NOT NULL PRIMARY KEY,
    [Pwd] nvarchar(MAX)
)
 
--加密
DECLARE @Pwd nvarchar(max)
SET @Pwd='测试加密'
--将varbinary类型转换成varchar类型
INSERT INTO Users VALUES ('admin',sys.fn_varbintohexstr(ENCRYPTBYPASSPHRASE('32423sd',@Pwd)))
 
SELECT * FROM Users
 
DECLARE @pv varbinary(max)
DECLARE @str nvarchar(max)
DECLARE @sql nvarchar(max)
--将varchar类型转换成varbinary类型
SELECT @str='0x0100000079e98bc2209c61038f9fc2eaaba24d6b8daad08fd98a41b6'
set @sql=N'set @p='+@str+N';'
    exec sp_executesql   @sql,
                         N'@p as varbinary(max) output',
                         @p=@pv output
PRINT @pv
--解密
SELECT CONVERT(VARCHAR(MAX),  DecryptByPassPhrase('123ASSDSS',@pv))
GO